Dental impression-tray.



VvJ. A. ROWSE. DENTAL IMPRESSION TRAY. APPLIOATI'ON TILE um. 1o. 1910.

,Patented Jan. 10, 1911.

Inl/em Y x T70@ pirvsc hr@ narran santas JOHN AMBROSE ROTV'SE, GF NEWQUAY, ENGLAND, ASSIGNOR OF ONE-HiLF T0 THE DENTAL :MANUFACTURING COIMIPANY, LIE/IITED,

0F LONDON, ENGLAND.

DENTAL IIPRESSION-TRAY.

ssn/ite.

Application filed August 19, 1910.

To all whom 'it may concern:

Be it known that l, JOI-IN AMBnosn Rowsn, a subject of the King of Great Britain formerly residing at T reviddo, near Liskeard, in the county of Cornwall, England, but now of Newquay, in the same county, have invented a certain new and useful improved Dental lmpression-'llray, of which the tollowing is a specification.

This invention relates to an impression tray as used in dentistry for holding a quantity of modeling material by means of which an impression can be taken of the palate or upper portion of a persons mouth.

According to the presentpract-ice it is customary to construct the rear and front portions of the tray in one piece and a disadvantage of such an arrangement resides in the tact that owing to the rigidity of the tray there is considerable ditliculty in so manipulating the same as to obtain a correct model or impression of the patients mouth. This is due to the fact that slight excess of pressure upon the back of the mouth near the soft palate, is liable temporarily to distort the same from its normal shape with the result that an inaccurate impression of this part of the mouth is obtained.

The present invention has for its chief object to obviate this ditliculty and to so construct the tray as to prevent excess of pressure being exerted upon the aforesaid portion of the mouth.

According to this invention the tray is formed with a front and rear portion for carrying the modeling material, the said portions being so constructed and arranged in relation to each other that upon pressure being exerted upon the front portion in a direction toward the palate of the patients mouth, the modeling material that is carried by such portion will impart a tilting motion in an upward direction to the rear portion of the tray with the result that the modeling material carried by such portion is gradually brought into intimate Contact with the back of the mouth without the pressure exerted thereon being sufficient to distort the same from its normal shape and so produce an incorrect impression.

In order that the said invent-ion may be clearly understood and be readily carried into the e'ect the same is described with Speccation of Letters Patent.

Patented Jan. l0, 191i.

Serial No. 578,038.

reference to the accompanying drawings, in which Figure l is a plan and Fig. 2 an inverted plan ot' dental impression tray constructed in accordance with this invention. Fig. 3 is a side elevation of the tray and Fig. 4; is a similar' view showing the rear portion ot the tray in its tilted condition. Fig. 5 is a section taken on line 5, 5, of Fig. l, and Fig. G is a similar View to Fig. l showing the two portions of the tray detached from each other.

A represents the front portion and B the rear portion of the tray.

In the arrangementshown the front portion A of the tray is formed with a curved channel a surrounding a bridge shaped portion a and extending across the space that intervenes between the inner sides of the channel a is a hinge pin a2. Formed in the base of the channel a at or near each end thereof and in advance of the hinge pin a2 is an aperture a3 for the purpose hereinafter described.

The rear portion B of the tray is formed at each side with a channel b and with an intervening tongue or bridge shaped portion ZJ which respectively constitute a continua- -tion of the curved channel a and of the bridge shaped portion c/ when the two portions of the tray are connected together. This connection is efected by causing the hinge pin a2 to enter a slot b2 -formed on each side of the bridge shaped portion b in which position the rear port-ion of the tray extends partly around the sides and partly underneath the bottom of the front portion.

TNhen a tray constructed in the manner described is charged with the modeling material and is pressed in an upward direction against the root or palate of a patients mouth, the pressure exerted upon the modeling material causes the latter to bear against the tongue or bridge portion Z7 and also to pass through the apertures a3 and exert pressure upon the base of the channels o. This pressure causes the rear portion of the tray to be tilted in the direction indicated in Fig. 4, with the result that the modeling material is brought into intimate contact with the back portion of the patients mouth with a yielding pressure that is so balanced or controlled by the aforesaid action of the modeling material as to be incapable of detrimentally affecting the formation of the back portion of the palate and thereby producing an incorrect impression.

lVhat I claim and desire to secure by Letters Patent of the United States is l. A dental impression tray comprising a front and a rear portion for carrying the modeling material, the said portions being hinged together transversely.

2. A dental impression tray comprising a front and a rear portion for carrying the modeling material, the said portions being hinged together transversely, and formed with overlapping surfaces.

3. A dental impression tray comprising a front port-ion having a bridge shaped portion surrounded by a curved channel having an aperture at or near each end thereof in the base, a hinge pin extending between the inner sides of the channel at the rear of the aforesaid apertures, and a rear portion arranged to engage with such hinge pin and to extend partly around the sides and partly underneath the bottom of the front portion.

4L. A dental impression tray comprising a front portion having a bridge shaped portion surrounded by a curved channel having an aperture at or near each end thereof in the base, a hinge pin extending between the inner sides of the channel at the rear of the 30 In testimony whereof I affix my signaturein presence of tWo Witnesses.

JOHN AMBROSE ROVVSE.

/Vitnesses ALBERT RoWn'r'r, E. J. CI-IIVETT. 

